Heating, ventilating, and air conditioning apparatus



p 19341 W. EwALs ET AL 1,972J66 HEATING, VENTILATING, MID AIP; coxni'rzomne APPARATUS Fn d Jul}; 7, i953 Patented Sept. 4, 1634 UNITED STATES PATENT OFFICE. I

Warren Ewald and John McElgin, Philadelphia,

Pa., assignors to John J. Nesbitt, Inc., Philadelphia, Pa., a corporation of Delaware Application July 7, 1933, Serial No. 6 9,425

4 Claims.

This invention relates to heating and ventilating or air conditioning apparatus and systems, and a principal object of the invention is to provide a system and apparatus of the stated character capable of delivering a measured quantity of fresh air while maintaining the required temperature condition.

Another object of the invention is to provide a system and apparatus of the stated character,

wherein provision is made for excluding the outside air and for re-eirculating the inside air during the initial heating operation.

Still another object of the invention is to provide in a system of the stated character means for insuring that the temperature of air introduced from the. apparatus shall not fall below a predetermin minimum to thereby prevent drafts. v

The invention further resides in the novel system of automatic control effecting the aforesaid desired results, all as hereinafter set forth and illustrated in the attached drawing, in which:

Figure 1 is a vertical sectional view of a unitary system made in accordance with our invention;

Fig. 2 is a diagrammatic view illustrating the various elements of the system and their relation one to another, and

Fig. 3 is a fragmentary sectional view illustrating a modification within the scope of the invention.

The invention will be more readily understood by reference to Fig. 1 of the drawing, which shows a unit assembly comprising a casing 1 having at its lower end intake openings 2 and 3 communi- 85 eating respectively with the room and with the outside air. These two ports communicate respectively'with chambers 4 and 5 separated by a partition 6 and at their tops communicating with a fan chamber 7. Communication between the chamber 7 and the chambers 4 and 5 is controlled by a pivoted damper 9 which in alternative extreme positions completely closes the openings between the respective chambers 4 and 5 and the chamber 7 and which in the intermediate positions provides for a joint communication in any desired proportions between the chambers 4 and 5 and the fan chamber 7. The fan 8 discharges air from the chamber 7 upwardly to a horizontally arranged discharge opening 11. and through a suitable heater 12 disposed below the discharge opening. Intermediate the chambers 4 and 5 and the chamber 7 is an air filter 13, which insures an adequate cleansing of the air before it reaches the motor and fan assembly.

65 The damper 9 is controlled in the present instance by a pneumatic motor 14 located in the chamber 4, and this motor is actuated by air drawn from a suitable pressure source and controlled by a thermostat 15. As shown in Fig. 2, this thermostat is positioned in the air line 17 connecting the motor 14 with the said source of compressed air (not shown), and functions in well known manner to regulate the pressure in the line in accordance with the temperatures to which the thermostat is subjected.

The system preferably comprises one or more direct radiators 18 located in the room which is controlled by means of a valve 19 pneumatically actuated and connected with the air line 17, as shown in Fig. 2. The system further includes a thermostat 21 located immediately above the heating element 12, which thermostat is operatively connected with the air line 17, and functions under predetermined conditions to release pressure from the air system. Flow of steam or other heating medium to the heating element 12 is controlled by means of a regulating valve 22 also pneumatically controlled and connected to the air line 17, as illustrated.

In preparing the system for operation, the 30 thermostat 15 may be set to exclude pressure from the air line 17 below a predetermined temperature, say 69 degrees. -When the room ternperature has risen above that point, the thermostat operates to admit pressure progressively to 35 the air line 17, the amount of pressure depending upon the temperature. The valve 19 controlling the direct radiatorl8 may be set to close at a given air pressure corresponding to a desired room temperature, say 70 degrees. The valve 22 controlling the unit radiator 12 may be regulated to remain open until the pressure in the line 17 reaches a predetermined amount, say for example eight pounds, at which pressure it is completely closed. This valve is also set to mod-. ulate between four pounds and eight pounds pressure, that is to say, the valve which remains wide open from zero to four pounds pressure starts to close at the last-named pressure and closes progressively as the pressure increases to eight pounds when, as previously stated the valve-closing is complete. Between four and eight pounds therefore the extent to which the valve is open or closed depends "at any moment upon the pressure in theline 17. The pneumatic motor 14 controlling the damper 9 may also be set to opcrate-under a predetermined pressure, say four pounds, to open the damper, and this initial opening movement of the damper is limited by a weight 23 opera'tively associated with the lever arm 24 of the motor 14, by .means of a slotted yoke as shown in Figure 2, this weight normally resting upon the floor of the chamber 4.

At four pounds pressure, therefore, the motor 114 will operate to open the damper 9 a predetermined amount, admitting outside air through the port 3 and chamber 5 to the fan chamber 7;

This initial opening of the damper is calculated tojadmit a measured amount of air to the room.

Asiireviously set forth, the initial opening of the damper is limited by engagement of the arm 24 'with the upper 'end of the weight yoke 23. The

weight is sufiicient to prevent further opening of the damper 9 until such time as the pressure in the line 17 has reached a predetermined amount in excess of the initial four pounds, say eight pounds, at which point the pressure is sufilcient to actuate the motor against the weight 23, elevating the weight from the floor and further opening the damper 9.

In Fig. 3, we have shown a modified form-of the damper motor control device by means of which at a predetermined temperature the initial predetermined opening of the. damper is effected. In this instance, instead of the weight 23 we employ a spring 230 which is held under compression between a plunger 26 and-the head 27 of a cylinder 28 in which the piston and the spring are mount- I held under compression by a pin 30 which projects ed. This cylinder is pivotally mounted at 29 to a suitable support structure, say the floor of the casing 1. In the present instance, the spring is from the plunger rod 31 and engagesthe top of the cylinder head 27. The rod 31 terminates at the top in a yoke or loop 32 through which the lever arm 24 of the lever 1'4 extends after the manner illustrated in Fig.2. In Fig. 3, the arm 24 is shown in the same relative position with respectto the yoke 32 as is the arm 24 in Fig. 2 with respect to the weight 23. By calibrating the spring 23, a predetermined pressure may be imposed through the medium of this spring upon the lever arm 24 when the latter has moved into the position engaging the top of the yoke 32, as'illusthe unit heater 12 and through the medium of the direct radiator 18. As the temperature in the room rises above 69 degrees, pressure is admitted by the thermostat 15 to the line 17, and when the room temperature reaches 70 degrees, the four pounds of pressure which at that temperature is admitted by the thermostat 15, closes the control valve 19 of the direct radiator. This four pound pressure in the line 17 also actuates the motor 14 to swing the damper 9 to a partially open position determined by the weight 23, admitting a measured amount of outside air from the chamber 5 to the fan chamber 7. The temperature of the room is now controlled by the unit heater 12, the valve 22 operating under the varying pressure in the line 17, as controlled by the thermostat 15, to admit more or less steam to the heater as required to maintain the desired temperature of 70 degrees. Should the temperature in the room increase to say 71 degrees, the excess air pressure admitted to the line 17 by the thermostat 15, totalling eight pounds, will close the'valve 22,'thereby rendering the unit heater 12 inoperative and at the same time will actuate the motor 14 to elevate the weight 23 and to still further open the damper 9,

admitting more of the outside air to the fan chamber 7. When as the result of this action the temperature of the room declines, the valve 22 will again be opened,- admitting heat to the unit heater 12 and the motor 14 will again permit the'damper 9 to close to the partly open position, insuring maintenance of the measured quantity of fresh air entering from without. If at any time duringthe operation'of the system, as described above, the temperature of the air entering the room from the casing 1 falls below 60 degrees (for example), the thermostat 21 will permit leakage of air from the line 17 to an extent opening the valve 22 and closing the damper 9; and eventually, if the leakage of air from the line 17 continues, re-opening the valve of the direct radiator 18 occurs.

. This system is well suited to schools and the like where a continuous predetermined volume of inflowing fresh air, depending for example upon the number of individuals in the room, is required; and where at the same time substantially uniform and safe temperatures are desirable with a complete absence of drafts. While we have described the system with pneumatic control, it will be understood that other control methods may be employed without departing .from the invention.

We claim:

1. The combination with a fluid supply duct, of a valve for regulating flow through said duct,

means for actuating the valve, a heating element for the fluid passing through the duct, and means for controlling passage of a heating medium to said element, and thermostatic control means for said valve-actuating means and for the heat control means operativeat a predetermined temperature to open the valve to a predetermined extent, said thermostatic control means being operative at increased temperatures to progressively decrease the amount of the heating medium passing to said element, and at a predetermined increased temperature to further open said valve.

2. In apparatus of the stated character, the combination with an air supply duct having a plurality of intake openings, of amixing damper operatively associated with said openings, and means for actuating said damper, a heating element positioned to heat the air passing through theduct, and means for supplying a heating medium to said element, and thermostatic control means for said heat supply and damper-actuating means operative at a predetermined temperature to actuate the damper-operating means to adjust the damper to a predetermined intermediate position-with respect to said intake open ings, and at a predetermined increased temperature to interrupt the passage of the-heating medium to the heating element and to further adjust the damper in the same direction to increase the extent of the one intake opening and to correspondingly decrease the extent of the other.

3. In apparatus of the stated character, the combination with an air supply duct having a recirculating inlet for indoor air and an inlet for outdoor air and an outlet through which said air is discharged into an indoor compartment, a mixing damper operatively associated with said inlets, heating means positioned to heat'the air passing through said duct, and'coordinating regulating mechanism for controlling-said heating means and the damper, said mechanism being adapted to adjust the damper from a position side air respectively, of a damper controlling said openings and determining the proportionate amounts of said recirculated and outside air admitted to the duct, a heating unitior the air passing through the duct, a valve controlling operation of said unit, thermally-controlled means operative at a predetermined temperature to open the damper to an initial position admitting a measured quantity of outside air to the duct, said means being operative at a higher temperature to further open the damper, and thermally-com.

trolled means operative between said predetermined and higher temperatures to modulate said valve between a predetermined degree of opening and the fully closed position.

. .WARREN EWALD.

JOHN McELGIN. 

